Abrasive sheet material



Nov. 5, 1940. H. G. BARTLING ET AL ABRASIVE SHEET MATERIAL originalFiled Jan. 29, 1929 Patched Nov. n5, 1940 UNITED STATES PATENT OFFICEAaAsIvE snnE'r MATERIAL Delaware Continuation of application Serial No.335,999,

January 29, 1

929. VThis application March 15, 1933, Serial No. 660,890

5 Claims. (Cl. 51-303) This invention relates to improvements inflexible, abrasive sheet material commonly known in the trade asabrasive paper or cloth, such as sand, flint, emery, garnet andaitici'al abrasives, and in the method of manufacturing the same, andone of the objects of the invention is to provide an improved abrasivesheet material of superior quality having great flexibility anddurability, without possessing any objectionable qualities such ascracking or tearing of the material, and which will be highly resistantto deterioration or wear.

Heretofore abrasive material of ,thisY character usually comprises abase of a flexible sheet fabric or paper to which grit or a layer ofabrasive particles are applied and secured by means of a binderinterposed between the sheet and theo abrasive particles, the binderhaving certain characteristics according to the nature of the work to beperformed. that is, for wet or dry Work.

This application is a continuation of our application S. N. 335,999illed January 29, 1929.

With such material considerable dimculty and inconvenience has beenexperienced as the frici tion between the sanding element and workcauses injury to binder and the abrasive particles quickly becomedetached. Furthermore, the fabric or paper may quickly wear or becometorn. If heavy fabric or paper is employed as a base, the work', andespecially the nner or higher grade oi' work, might be marred, scratchedor otherwise injured thereby.

It is one of the objects of the present invention to provide an improvedabrasive sheet material in which the bond or binder and the fabric orpaper will be dispensed with, and the abrasive material will be attachedor secured in position to a flexible body portion by means oi the in-.herent qualities of the material or substance constituting or formingthe body portion of the sheet material.

A further object is to provide an improved abrasive element embodyingonly a flexible body portion and an abrasive element applied and securedthereto or embeddedmtherein without the employment of an adhesive 6rbinding material between the body portion of the element and theabrasive material.

In carrying the invention into operation the body portion of theabrading element is formed of a flexible material such as cellulose orany other suitable substance which initially is `preferably in the formof a liquid of any desired consistency, and preferably a plasticmaterial capable of clinging to a surface while drying, the substancebeing of such a nature that an abrasive may be applied thereto ormounted thereupon. The substance of which the body portion is composedshould also be of such a nature and material that after the solventshave been evaporated it may be stripped or removed from such surface andwhen rem'oved will be flexible and of any desired thickness with theabrasive firmly attached or secured thereto. The cellulosic materialwhich we may employ may be cellulose nitrate, cellulosexanthogenate orcellulose acetate, all of which are reactive to the normal solventstherefor. If desired, these materials may be reinforced by the additionof vai-- ious gums or gum resins. The solvents which we may employ maybe acetone, with or Without a ketone, and any other of the vknownsolvents for these cellulosic materials. These cellulosic materials havethe characteristic of relatively rapidly solidifying when formed into alayer, the side of which contacts an adjacent surface as willhereinafter appear, solidifying before the exposed surface.

The liquid is manipulated or formed in any desired or suitable mannerinto a sheet of any desired length, width and thickness and is subjectedto a drying operation preferably so that one side or face thereof willdry more rapidly than the other, and suiciently to permit the materialto be advanced or moved forward, and at the same time leaving the topsurface tacky or sticky To this surface, before the same becomes dry, isapplied in any suitable manner, deposited thereupon, or embeddedtherein, the abrasive material, preferably in the form of sand,remery,flint or garnet, or like material, or the artificial abrasives which areused in many instances, in preference to the natural abrasivesmentioned.

As the material forming the body portion of this product solidies ordries into the exible l sheet, the grit or abrasive material becomesfastened or secured thereto by the inherent qualities of the materialforming the body portion of the element, and the abrading material willbe fastened to the body portion more securelythan if an, adhesive isapplied to secure the abrading material to a cloth, paper or otherbacking.

Furthermore, with the present invention the product consists of buttwoelements, one of which is a flexible substance, preferably though notnecessarily non-metallic, and the other an abrasive material, the twobeing fastened or se- Y while the latter is plastic or semi-dry, itwillbecome a part of the flexible body portion as the cured togetherwithout the added use of adhesives, /binders or backing.

As the abrasive is applied to the body portion,

latter solidies or hardens through evaporation of the solventstherefrom.

During the operation the material will harden or solidify around theatoms or particles of the abrading material and firmly hold or securethem to the surface of the body portion of the element.

This abrasive sheet may also be producedn in another manner as theplastic or semi-plastic body portion may be formed and allowed to becomepartially or thoroughly dry or solidified,

and at a subsequent time apply the abrasive to the `surface thereof.

If this latter method is employed, then one face of the body portionthus produced may be dampened with the liquid of Ithe same material asthe body portion, or with a solvent in a liquid state so as to renderthe surface of the body portion sticky or tacky, after which theabrasive material may be 'deposited upon, applied to or embedded in suchsurface in any desired manner. A further drying or solidiiication oftheproduct thus produced will cause the particles of the body to firmlygrip around the atoms or particles of the abrasive material.

If desired and in order to reinforce the body portion of the abradingelement, a iiexible reinforcing element, preferably, although notncessarily non-metallic, may be embedded or molded therein with the bodyportion of the abradin'g element formed around or about the same.

The methods disclosed herein for producing an abrasive article of, thisinvention may be carried out by various apparatus and in the figures ofthe drawing we have illustrated embodiments of apparatus for producingan abrasive article of the character described herein.

In the drawing:

Figure 1 is a diagrammatic view-of apparatus for carrying out one of themethods disclosed herein.

Figure 2 is a modified form of the invention and Figure 3 is a stillfurther modied form.

Referring now to Figure l, there is provided a carrier or conveyor,preferably of av n exible but stable nature indicated at 5, said carrierhaving a relatively smooth exposed upper surface 6, t which is appliedthe cellulosic compound forming the backing of the abrasive article tobe produced, the path of the conveyor 5 being changed in directionasindicated at 1 by passing over a suitable roller or over propellingmeans.

above the conveyor,` and spaced the desired distance therefrom weprovide a hopper 8 for binder material which is extended to serve thepurpose of the backing herein described This backing material,preferably of a cellulosic character, is indicatedflowing in plasticform from the hopper V8 at 9 into a layer I0 on the conveyor 5.

Owing to the nature of the adhesive employed the back surface thereof incontact with Ithe belt or conveycr 5 has a tendency to solidify orharden more rapidly Whrre it contacts at I2 with said conveyor than atits outer surface I3; the outer surface remains in a plastic orsemi-plastic state as the backing material or binder passes beneath thehopper I4, which hopper is adapted to contain a-pulverulent abrasivematerial I5 for deposition on the backing I!) which abrasive is appliedto the plastic surface of the backing I touform a layer of abrasive I6.

As the layer or backing I0 having the grit incorporatedthereinmovesalong the conveyor by adhesion thereto and approaches the deflectedportion 1 of the conveyor,y the backing engages a stripping blade I1positioned so as to have its reduced edge I8 presented tangentially tothe conveyor thus stripping the backing and its grit layer from theconveyor.

In order to cause the Vpreliminary setting of the backing or tohastenthe setting of" the tacky surface of the backing I0, cooling airblasts may be directed against the underside of 'the conveyor asindicated at I9 and 20. 20.

The air blast delivered from the nozzle I9 is applied before the layerof binder material reaches the point of deposition of the grit and theother air blasts 20 are applied after the binder passes the grit hopper.

It will be understood ,that the conveyor may Vbe of any desired lengthdepending upon the ingredients employed in the backing layer and Ithetime interval betweenthe deposition of bin'der and deposition of gritrequired to produce the desired results. An auxiliary drying nozzle 2Imay be provided if desired for hastening setting kof the backing at theend of the flight to -the conveyor. i n

Referring now to Figure 2, the assembly here issubstantially the sameasthat shown in Figure 1 and a detailed description of all of the partsthereof is therefore not included. For some purposes it may be desiredto allow the backing I0 nto become st beforereceiving the grit, but ifthis is done as hereinabove explained, the'means for supplying a solventin a liquid state for rendering the exposed surface of the backingy I0tacky may be employed. Such a means is. dise closed at 22 and includes anozzle controlled by valve 23.

Referring now to Figure 3, the apparatus therein disclosed issubstantially the same as that shown in either Figure 1 or 2, or both,as may be desired, a conveyor 5a being provided having a divergentportion 1a. y

Upon the conveyor 5a is applied a backing or reinforcing element 25 andthis element is moved by any suitable means along with the conveyor 5abeneath the binder-containing hopperl 26 and the grit-containing hoppier21.

The binder layer of cellulosic material or the like is shown at 2Bissuing from the hopper 26 and adapted to receive the grit layer 29supplied from the hopper 21. y

If desired, a process of moistening the exposed surface 30 of the binderlayer 28 may be resorted to by the provision of the solvent deliveringnozzle 3I shown in dotted lines.

It will be understood that the several forms of the apparatus-are purelydiagrammatic and may be varied structurally to suit conditions ofoperationin the course of actual manufacture of the abrasive article.

ticles become a part of ythe body portion without ,manner in which abacking and the provision of a' binder or adhesive between the bodyportion and the abrading particles will be dispensed with.

What is claimed as neW is:

1. The method of manufacturing flexible abrasive material which consistsin providing a substance in plastic form, then shaping said material bycasting and partially solidifying the same progressively from thecasting surface and leaving an exposed surface unsolidied, then applyingabrasive particles to the unsolidified surace, and then completelysolidifying such surace.

2. The method of manufacturing flexible abrasive material which consistsin providing a nonmetallic substance in plastic form, then shaping saidmaterial by casting and partially solidifying the same progressivelyfrom the casting surface and leaving an exposed surface unsolidified,then applying abrasive particles to the un- 4solidied surface, and thenvsolidifying such surface by evaporating the solvents therefrom, andsolidifying the entire article so cast with the abrasive particles insitu.

3. The method of manufacturing abrading material which consists incasting upon a continuously moving surface a plastic mass from a liquidwhich adheres to said surface and becomes a flexible substance afterevaporation of its solvents, then applying abrasive particles to theexposed face of such substance so cast While said face is still in aplastic state, then evaporating the solvents, the abrading particlesbeing'l secured to such substance solely by solidifying the adjacentportion of the substance about said particles, and then removing thecast body portion with the abrasive fastened thereto, from the surfaceupon which the body has been formed.

4. A process for forming an abrasive article which includes as stepsthereof, forming a plastic body on a movable conveyor, and causing sameto adhere thereto, drying or setting one surface of said body to providea cast surface While leaving the other surface tacky, applying a layerof abrasive particles to said tacky sur-r face, and then setting thebody for retaining the abrasive particles therein and removing said bodyfrom the conveyor along the cast surface.

5. The method of producing exible sheet abrasive material which consistsof casting upon a continuously moving supporting' surface a plasa solidiexible mass that will retain abrasive grains embedded in the surfacethereof, then applying abrasive grainsv to the surface of the plasticmass before it becomes too hard to receive said abrasive grains, thenhardening the plastic mass by evaporating the solvent, and then removingthe 1hardened plastic mass from the supporting surface. g

' HOWARD G. BARTLING.

EILSWORTH B.` OVERSHINER.

" tic mass of liquid consistency in a volatile solvent,which is capableof being converted intov ORRTIRIOATR OF CORRECTION. Patent No.2,220,1LLO. November 5, 19m.

HOWARD G. BARTLING, RT AL.

is hereby certified that error appears in the printed specification of'the above numbered patent requiring correction as follows: Page 5, firstcolumn, line 18, claim l,'after"f`ace insert and the material with theabrasive particles in situ; and that the said Letters Patent should beread with this correction therein that the same may conform to therecord Of the Case 4in the Patent Office.

Signed and sealed this 7th day of' September, A. D. 19MB.

K Henry Van Arsdale (Seal) Acting Commissioner of Patents.

